Solar battery metal electrode structure and battery assembly

ABSTRACT

A metal electrode structure for a solar battery and a battery assembly are provided. The structure of the metal electrode for the solar battery includes multiple main grid lines provided parallel to one another and multiple fine grid lines perpendicular to the main grid lines. Spacing between adjacent two main grid lines is defined as L, and a distance between two end points of each fine grid line is less than L. And connecting ends of adjacent two fine grid lines of the multiple fine grid lines between adjacent two main grid lines are connected to different main grid lines of the adjacent two main grid lines.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of international patent applicationNo. PCT/CN2021/110867, filed on Aug. 5, 2021, which itself claimspriority to Chinese patent application No. 202021942580.3, filed on Sep.8, 2020, and titled “SOLAR BATTERY METAL ELECTRODE STRUCTURE AND BATTERYASSEMBLY”. The contents of the above identified applications are herebyincorporated herein in their entireties by reference.

TECHNICAL FIELD

The present disclosure relates to the field of solar photovoltaictechnology, and in particular, to a solar battery metal electrodestructure and a battery assembly.

BACKGROUND

In a solar battery, metal electrodes are a very important part of thebattery structure and have been under constant optimization. The mainrole of the electrodes is to minimize a lateral transmission resistanceof photo-generated current, that is, to improve an efficiency ofcollecting the photo-generated carriers and thus to improve aphotoelectric conversion efficiency of solar batteries. Therefore, thedesign of a metal electrode pattern is particularly important. A shadingarea of the electrode and a collection efficiency of carrier areimportant in the design of the metal electrode pattern. In order tocollect as many photo-generated carriers as possible and reduce thelateral transmission resistance, spacing between adjacent metalelectrodes can be reduced, which means that the number of electrodesneeds to be increased or the width of a single electrode should beincreased. However, the shading area of the electrode may be increasedand a light receiving area of the battery may be reduced, resulting inlow battery conversion efficiency. At the same time, an increase of thenumber of electrodes will also increase the amount of metallic silverpaste, leading to more cost. On the contrary, when the spacing betweenadjacent metal electrodes are wide and the number of electrodes issmall, it is conducive to reducing the shading area of the electrode andincreasing the light receiving area. Since the number of electrodes issmall, the amount of silver paste is reduced, which helps to reduce thecost. However, this will make the transverse transmission resistanceincrease, which affects the filling factor of the battery, and thenaffects the conversion efficiency of the battery. Therefore, the designof metal electrode patterns should be balanced between the two aspects.

Currently, the method for producing the metal electrodes used in thephotovoltaic industry is screen printing technology. A structure of themetal electrode usually contains interlocking parallel metal grid lines,i.e., main grid lines and fine grid lines. The fine grid lines areparallel to each other, and a certain spacing is defined betweenadjacent two fine grid lines and the number of the fine grid lines islarge. The main grid lines are perpendicular to the fine grid lines.Spacing between adjacent two main grid lines is relatively wide, and thenumber of the main grid lines is small, which has developed from theinitial 3 busbars (3BB) to the current 5 busbars (5BB), 9 busbars (9BB)and 12 busbars (12BB). The fine grid lines are mainly used to collectphoto-generated carriers, and the main grid lines collect and output thecarriers collected by the. In order to improve the collectionefficiency, the main grid lines and fine grid lines are usuallyinterleaved to reduce the contact resistance at the same time. However,the above design has a large shading area on the one hand, and highsilver paste consumption on the other hand, resulting in low batteryconversion efficiency and high production cost. Moreover, a height ofthe interlaced main grid lines and fine grid lines is higher than thesurrounding area, which can easily cause battery breakage and hiddencracks when subjected to external force.

SUMMARY

In order to overcome the defects of the conventional art, the presentdisclosure provides a metal electrode structure of a solar battery, anda battery assembly, which have high photoelectric conversion efficiencyand low silver paste consumption. The electrode structure can lowerrisks of battery breakage and hidden cracks.

In order to solve the technical problems above, the present disclosureprovides the following technical solution.

A metal electrode structure of a solar battery, includes a plurality ofmain grid lines parallel to each other, and a plurality of fine gridlines disposed perpendicular to the plurality of main grid lines.Spacing between adjacent two of the plurality of main grid lines isdefined as L, and the distance between two end points of each of theplurality of fine grid line is less than L. Connecting ends of adjacenttwo of the plurality of fine grid lines between adjacent two of theplurality of main grid lines are located on different main grid lines,respectively.

Furthermore, the distance between two end points of each of theplurality of fine grid lines is greater than or equal to 0.75 L.

Furthermore, the plurality of main grid lines and the plurality of finegrid lines are straight lines or wavy lines.

Furthermore, the plurality of main grid lines are provided with hollowsections.

Furthermore, the plurality of main grid lines are regarded as aMulti-Busbar, the number of the plurality of main grid lines is definedas M, and M is smaller than or equal to 50 and greater than or equal to2.

Furthermore, L is in a range of 1 millimeter to 50 millimeters.

Furthermore, spacing between adjacent two of the plurality of fine gridlines is in a range of 1 millimeter to 5 millimeters.

Furthermore, a width of each of the plurality of main grid lines is in arange of 1 micrometer to 5 millimeters; and a width of each of theplurality of fine grid lines is in a range of 1 micrometer to 100micrometers.

A battery assembly includes a plurality of battery pieces. The pluralityof battery pieces includes the metal electrode structure describedabove.

The technical solution of the present disclosure has the followingbeneficial effects.

In a metal electrode structure of a solar battery of the presentdisclosure, since the plurality of main grid lines and the plurality offine grid lines are interlace with each other, and a length of the finegrid line is less than spacing L between adjacent two main grid lines, alength of the metal grid electrode can be reduced without effecting alateral transmission resistance of carriers and collection of thecarriers by the metal grid electrode. Therefore, a consumption of thesilver paste, and a cost of the production can be reduced, a shadingarea can reduced, and a conversion efficiency of the battery can beimproved. In the present disclosure, by optimizing a design of aconjunction between the fine grid line and the main grid line, a risk ofhidden cracks of the battery can be reduced, and a reliability of thebattery assembly can be improved.

In the metal electrode structure of the present disclosure, bydecreasing a length of the fine grid lines, at least 15% of the shadingarea can be reduced, and at least 10% of the silver paste consumptioncan be saved, and the conversion efficiency of the battery can beimproved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a metal electrode structure of a solarbattery of a first embodiment of the present disclosure.

FIG. 2 is a partial structural schematic diagram of a metal electrodestructure of a solar battery in the present disclosure.

In the figures, 1 represents a main grid line, and 2 represents a finegrid line.

DETAILED DESCRIPTION

The following embodiments provide a more complete understanding of thepresent disclosure for the skilled in the art, but they are not alimitation on the scope of protection of the present disclosure. By “anembodiment” or “embodiment” herein is meant a particular feature,structure, or characteristic that may be included in at least oneembodiment of the present disclosure. The phrase “in an embodiment”appearing in various places in the present specification does not meanthe same embodiment, nor is it a separate or selective embodiment thatis mutually exclusive with other embodiments

Referring to FIG. 1 and FIG. 2 , the present disclosure provides a metalelectrode structure of a solar battery. The metal electrode structureincludes a plurality of main grid lines 1 parallel to each other, and aplurality of fine grid lines 2 disposed perpendicular to the main gridlines. A spacing between adjacent two main grid lines 1 is defined as L,and a distance between two end points of each of the plurality of finegrid line 2 is less than L. Connecting ends of adjacent two fine gridlines 2 of the plurality of fine grid lines 2 between adjacent two maingrid lines 1 are connected to different main grid lines 1 of theadjacent two main grid lines 1. The plurality of fine grid lines can besegmented lines in parallel with each other. The plurality of fine gridlines 2 can define staggered fine grid lines 2, so as to ensurecollection of photo-generated carriers. The electrode structure of thepresent disclosure optimize a connection between the fine grid lines andthe main grid lines (that is, both ends of the fine grid lines 2 areperpendicularly connected to the main grid lines 1, respectively) in theconventional art, which overcomes problems of a large shading area, alow photoelectric conversion efficiency, and high silver pasteconsumption.

In some embodiments of the present disclosure, the distance between twoend points of each of the plurality of fine grid lines 2 can be greaterthan or equal to 0.75 L. Since the distance between the two end pointsof each of the plurality of fine grid lines are controlled in the rangeof 0.75 L to L, not only the collection of the photo-generated carriercan be guaranteed, but also the silver paste consumption can becontrolled in a suitable area to effectively control the productioncost. When the linear distance between the two end points of each of theplurality of fine grid lines is less than 0.75 L, the collection of thephoto-generated carrier may be influenced, so as to lower thephotoelectric conversion efficiency in some degree.

In some embodiments, the number of the plurality of main grid lines 1 isdefined as M (MBB, multiple Busbar), and M is smaller than or equal to50 and greater than or equal to 2. In some embodiments, the number ofthe plurality of main grid lines can be 5, 9, 12, and the like,according to actual need.

In some embodiments, L can be in a range of 1 millimeter to 50millimeters. In some embodiments, L can be selected from 1 millimeter, 2millimeters, 5 millimeters, 6 millimeters, 8 millimeters, 10millimeters, 12 millimeters, 15 millimeters, 18 millimeters, 20millimeters, 25 millimeters, 30 millimeters, 35 millimeters, 40millimeters, 45 millimeters, 48 millimeters or 50 millimeters. Bydesigning the spacing between adjacent two main grid lines in the rangeof 1 millimeter to 50 millimeters, the number of the main grid lines issuitable, the number of the fine grid lines disposed between the maingrid lines is also suitable, and the shading area is suitable, so thatthe photoelectric conversion efficiency can be effectively improved.

In some embodiments, a spacing between adjacent two fine grid lines ofthe plurality of fine grid lines can be in a range of 1 millimeter to 5millimeters. In some embodiments, the spacing between adjacent two finegrid lines can be selected from 1 millimeter, 1.2 millimeters, 1.5millimeters, 1.8 millimeters, 2 millimeters, 2.5 millimeters, 2.8millimeters, 3 millimeters, 3.2 millimeters, 3.5 millimeters, 3.8millimeters, 4 millimeters, 4.2 millimeters, 4.5 millimeters, 4.8millimeters or 5 millimeters. By controlling the spacing between theadjacent two fine grid lines in the range of 1 millimeter to 5millimeters, the shading area is suitable, the lateral transmissionresistance of the photo-generated carriers is small, and thephotoelectric conversion efficiency is high. By designing the spacingbetween adjacent two main grid lines in the range of 1 millimeter to 50millimeters, the shading area is suitable, the lateral transmissionresistance of the photo-generated carriers is small, and thephotoelectric conversion efficiency is high. When the spacing betweenthe adjacent two fine grid lines is less than 1 millimeter, the numberof the electrodes may significantly increases. Therefore, the shadingarea may be surely increased, and a light receiving area of the batterymay be decreased, leading to low conversion efficiency of the battery,increase silver paste consumption, and increase of the production cost.When the spacing between the adjacent two fine grid lines is greaterthan 5 millimeters, the lateral transmission resistance may increase,which may influence a filling factor of the battery, thereby influencingthe conversion efficiency of the battery.

In some embodiments, a width of each of the plurality of main grid linescan be in a range of 1 micrometer to 5 millimeters. When the width ofeach of the plurality of main grid lines is in a range of 1 micrometerto 5 millimeters, the shading area is suitable, the photoelectricconversion efficiency is high, the silver paste consumption is low andthe production cost is low. In some embodiment, the width of each of theplurality of main grid lines can be selected from 1 micrometer, 2micrometers, 3 micrometers, 4 micrometers, 5 micrometers, 6 micrometers,8 micrometers, 10 micrometers, 20 micrometers, 50 micrometers, 80micrometers, 100 micrometers, 0.5 millimeters, 1 millimeter, 1.5millimeters, 2 millimeters, 2.5 millimeters, 3 millimeters, 3.5millimeters, 4 millimeters, 4.5 millimeters, or 5 millimeters.

In some embodiments, a width of each of the plurality of fine grid linescan be in a range of 1 micrometer to 100 micrometers. In someembodiments, the width of each of the plurality of fine grid lines canbe selected from 1 micrometer, 2 micrometers, 3 micrometers, 4micrometers, 5 micrometers, 6 micrometers, 7 micrometers, 8 micrometers,10 micrometers, 15 micrometers, 20 micrometers, 25 micrometers, 30micrometers, 35 micrometers, 40 micrometers, 45 micrometers, 50micrometers, 55 micrometers, 60 micrometers, 65 micrometers, 70micrometers, 75 micrometers, 80 micrometers, 85 micrometers, 90micrometers, 95 micrometers, 100 micrometers. When the width of each ofthe plurality of fine grid lines is in the range of 1 micrometer to 100micrometers, the shading area is suitable, the photoelectric conversionefficiency is high, the silver paste consumption is low and theproduction cost is low.

In some embodiments, of the present disclosure, the plurality of maingrid lines can be provided with hollow sections. In this way, the silverpaste consumption can be further lowered on the premise that thephotoelectric conversion efficiency is ensured. The specific ratio of alength or an area of the hollow section to those of the main grid line 1are not limited, which can be limited according to actual manufacturingtechnique.

In some embodiments of the present disclosure, the plurality of maingrid lines 1 and the plurality of fine grid lines 2 can be selected fromat least one of straight lines or wavy lines. For example, both theplurality of main grid lines 1 and the plurality of fine grid lines 2are wavy lines; optionally, the plurality of main grid lines 1 arelinear lines, and the plurality of fine grid lines 2 are wavy lines.

The present disclosure further provides a battery assembly. The batteryassembly can include a plurality of battery pieces, which includes themetal electrode structure described above.

First Embodiment

In the present embodiment, the number of the plurality of main gridlines was 9. A spacing between the plurality of main grid lines was L. Alength of a fine grid line was 0.75 L. L was 16.79 millimeters. Aspacing between adjacent two fine grid lines of the plurality of finegrid lines was 1.99 millimeters. A width of the main grid line was 0.13millimeters. A width of the fine grid line was 50 micrometers. Both themain grid lines and the fine grid lines were linear lines.

Second Embodiment

In the present embodiment, a length of the fine grid line was 0.8 L, andthe other structures of the metal electrodes were the same as those ofthe metal electrodes in the first embodiment.

Third Embodiment

In the present embodiment, a length of the fine grid line was 0.83 L,and the other structures of the metal electrodes were the same as thoseof the metal electrodes in the first embodiment.

Fourth Embodiment

In the present embodiment, a length of the fine grid line was 0.86 L,and the other structures of the metal electrodes were the same as thoseof the metal electrodes in the first embodiment.

Fifth Embodiment

In the present embodiment, the main grid lines were provided with hollowsections (not shown in the figures). A distance between two end pointsof fine grid lines being perpendicularly connected to the hollowsections of the plurality of fine grid lines was 0.75 L. The otherstructures of the metal electrodes were the same as those of the metalelectrodes in the first embodiment.

Sixth Embodiment

In the present disclosure, the main grid lines were provided with fishspear-shaped hollow section. A distance between two end points of finegrid lines being perpendicularly connected to the hollow sections of theplurality of fine grid lines was L. The other structures of the metalelectrodes were the same as those of the metal electrodes in the firstembodiment.

Seventh Embodiment

In the present embodiment, a distance between two end points of finegrid lines being perpendicularly connected to the hollow sections of theplurality of fine grid lines was L, and the other structures of themetal electrodes were the same as those of the metal electrodes in thesecond embodiment.

Comparative Embodiment

In comparative embodiments, both ends of the fine grid lines wereperpendicularly connected to the main grid lines, respectively. Theother structures of the metal electrodes were the same as those of themetal electrodes in the first embodiment.

The battery pieces of the present embodiment and the battery pieces inconventional art were tested, short-circuit currents (ISC), voltages ofopen circuit (VOC) of the battery piece of the present embodiment wereobtained, and the filling factor (FF) and the conversion efficiency(Eff) were calculated. The specific values were shown in Table 1.

TABLE 1 Performances and silver paste consumption of battery pieces inthe conventional art and the first embodiment Silver paste consumptionof the fine The number of grid lines on a front Reduction of batterypieces I_(SC) V_(OC) FF Eff surface of the battery silver paste (pcs)(A) (V) (%) (%) (g) (%) Comparative embodiment 50 9.53061 0.7460682.6129 23.31 0.0505 / First embodiment 50 9.57161 0.74743 82.18 23.330.044 12.87%

Referring to Table 1, compared with the electrode having a conventionalstructure, the conversion efficiency of the electrode structure of thepresent disclosure was improved, and the silver paste consumption waslowered for 12.87%.

It could be concluded from carriers transmission calculation that bydecreasing lengths of the fine grid lines 2 in the metal electrodestructure of the solar battery in the first embodiment to the seventhembodiment, the shading area was decreased for at least 15%, the silverpaste consumption was decreased for at least 10%, and the conversionefficiency of the battery was increased.

In view of above, in the metal electrode structure of a solar battery inthe present disclosure, since the main grid lines and the fine gridlines are interlaced, and a length of the fine grid line in a range of0.75 L to L (a spacing between adjacent two main grid lines is definedas L), the length of the metal grid electrode could be reduced withoutinfluencing lateral transmission of the carriers and collection of thecarriers by the metal grid electrode. Therefore, not only the silverpaste consumption is lowered, but also the shading area is decreased,thereby increasing the conversion efficiency of the battery and loweringthe production cost. At the same time, in the present disclosure, byoptimizing the conjunction between the fine grid lines and the main gridlines, a risk of hidden cracks of the battery can be reduced, and areliability of the battery assembly can be improved.

Taking the above-mentioned ideal embodiments based on the presentdisclosure as an inspiration, the above description allows the skilledin the art to make various changes and modifications without deviatingfrom the technical idea of the present disclosure. Any modification,equivalent substitution, improvement, etc. made within the spirit andprinciples of the present disclosure shall be included in the scope ofprotection of the present disclosure. The technical scope of theinvention is not limited to the contents of the specification, but mustbe determined according to the scope of the claims.

What is claimed is:
 1. A metal electrode structure of a solar battery, comprising a plurality of main grid lines parallel to each other, and a plurality of fine grid lines disposed perpendicular to the plurality of main grid lines, spacing between adjacent two of the plurality of main grid lines is defined as L, and a distance between two end points of each of the plurality of fine grid lines is less than L, and connecting ends of adjacent two of the plurality of fine grid lines between adjacent two of the plurality of main grid lines are located on different main grid lines, respectively.
 2. The metal electrode structure of the solar battery of claim 1, wherein the distance between two end points of each of the plurality of fine grid lines is greater than or equal to 0.75 L.
 3. The metal electrode structure of the solar battery of claim 1, wherein the plurality of main grid lines and the plurality of fine grid lines are selected from at least one of straight lines or wavy lines.
 4. The metal electrode structure of the solar battery of claim 1, wherein the plurality of main grid lines are provided with hollow sections.
 5. The metal electrode structure of the solar battery of claim 1, wherein the plurality of main grid lines are regarded as a Multi-Busbar, the number of the plurality of main grid lines is defined as M, and M is smaller than or equal to 50 and greater than or equal to
 2. 6. The metal electrode structure of the solar battery of claim 1, wherein L is in a range of 1 millimeter to 50 millimeters.
 7. The metal electrode structure of the solar battery of claim 1, wherein spacing between adjacent two of the plurality of fine grid lines is in a range of 1 millimeter to 5 millimeters.
 8. The metal electrode structure of the solar battery of claim 1, wherein a width of each of the plurality of main grid lines is in a range of 1 micrometer to 5 millimeters; and a width of each of the plurality of fine grid lines is in a range of 1 micrometer to 100 micrometers.
 9. A battery assembly, comprising a plurality of battery pieces in electric connection with each other, wherein the plurality of battery pieces comprises the metal electrode structure of claim
 1. 